Sound absorption performance of a lightweight ceramic foam

Porous materials can be effective for sound absorption and noise reduction. A kind of lightweight cellular ceramic foam with bulk density of 0.38-0.56 g cm(-3) was successfully prepared by conventional molding with pore forming agent. The porosity is from 76.4% to 83.7% for the sample with relatively large pores (the average pore size: 5.3-5.6 mm), and from 74.1% to 81.1% for the sample with relatively small pores (the average pore size: 1.5-1.7 mm). The effects were investigated for processing parameters on the structure of samples, and for the pore size, sample thickness and porosity on the sound absorption performance of samples. The results show that the absorption performance of the ceramic foam product with relatively large pores may be superior to that with relatively small pores in the case of the approximately same porosity. The first absorption peak moves from a higher frequency to a lower frequency with the increase of sample thickness. When the porosity increases, the average sound absorption coefficient increases for all of the samples, and the first absorption peak moves from a higher frequency to a lower frequency for the sample with relatively large pores but does not change for that with relatively small pores.